Heat insulating material



June 30, 1942. w. F.'ASTLEY 2,288,311

HEAT INSULATING MATERIAL Filed Feb. 4, 1938 2 Sheets-Sheet 1 June 30, 1942. w, F. ASTLEY 2,288,311

HEAT INSULATING MATERIAL Filed Feb. 4, 1938 2 Sheets-Sheet 2 fnuemzarf Patented June 30, 1942 HEAT INSULATING MIATERIAL William F. Astley, Cicero, Ilia, assignor to Union Asbestos & Rubber Company, Chicago, 111., a

corporation of Iilinoi Application February 4, 1933, Serial No. 188,720

(Cl. ESQ-42b) The present invention relates to heat insulating materials'and methods of making these materials, and is particularly concerned with the provision of improved insulating materials particularly adapted for use at higher temperatures.

In addition to being adapted for higher temperatures, however, the insulating materials made according to the present invention have improved characteristics over the insulating materials of the prior art, due to the structure and arrangement of the elements of the insulation, and these materials may be used in all places where flexible or blanket insulation of the prior art may be used.

One of the objects of the invention is the provision of an improved flexible and highly efficient insulating material which is capable of meeting special conditions, such as use at higher temperatures, as, for example, up to 750 degrees 01 L000 degrees F.

Another object of the invention is the provision of an improved insulating material adapted to be constructed of insulating fibers which are otherwise not adaptable for weaving according to ordinary methods and which possesses the characteristics of flexibility, strength, ease of application to flat or curved surfaces, resiliency,

durability, and lightness to a high degree.

Another object is the provision of an improved form of insulation which is built up of 73 large, loose, soft bodies of special insulating fibers, such as, for example, Amosite fibers, which are thoroughly carded and opened to form a mass of high volume and low weight and in which the bodies of insulating units are bound together, but not confined nor shaped by the enclosing strands in such manner that the opened and carded fibers of one insulating unit may intermingle with the adjacent units to form a practically continuous felt body characterized by an absence of cracks and by a substantially homogeneous fibrous structure.

Another object is the provision of an improved insulating material which is not only adapted to be used for flat or curved surfaces, but may be made into flange covers and other odd sized covers, and covered with a jacket of asbestos cloth which is sewed in place or secured by lacing with asbestos twine.

Another object is the provision of an improved method of making insulating materials which have a high insulating efficiency, a low weight, and which are exceedingly durable, and which maintain their desirable characteristics through vibration or other deteriorating influences.

Other objects of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the two sheets of drawings accompanying this specification,

Fig. 1 is a full sized elevational view of an insulating unit, from which the insulating materials of the present invention are constructed;

Fig. 2 is an end elevational View;

Fig. 3 is a diagrammatic elevational View on a smaller scale;

Fig. 4 is a top plan view of a blanket or sheet of insulating material, constructed according to the present invention;

Fig. 5 is a side elevational view of such insulation;

Fig. 6 is a cross-sectional view, taken on the plane of the line 6-6 of Fig. 4, looking in the direction of the arrows;'

Fig. 7 is a sectional View on a greatly enlarged scale, taken through one of the threads or cords which is used for binding the fibers together;

Fig. 8 is an elevational view, also on a greatly enlarged scale, of the same thread or cord, showing. its structure;

Fig. 9 is a reproduction of curves showing the B. t. u.s per square foot per inch thickness per hour per degree of Fahrenheit temperature difference.

The present invention is to be carefully distinguished from the insulating materials of the prior art employing ropes or rovings, and for the purpose of this application I will state that the most important distinction between a roving and the present insulating units is that the fibers of a roving are twisted and rubbed during the twisting action in such manner that they become more uni-directional than the fibers in the present units, and being twisted, they are more dense and compact, like one of the strands of a rope.

The rovings of the prior art are also, at least to some degree, separate units when they are assembled in the flexible insulation because of their twisted and compacted condition, which is the result of an effort to provide such rovings with tensile strength sufiicient for weaving and for maintaining their form in the insulation.

The insulating units of the present invention may be stated to have no predetermined shape, and they comprise the carded and opened asbestos fibers in the form of sliver. which is the form having the highest volume, the lightest weight, and the greatest insulating value. Although the insulating unit of which the insulation is made is shown as an elongated member, its shape is very irregular, and it comprises the asbestos fibers in the form of sliver and sufiicient interlacing threads, cords, or strands to confine this sliver in the form of a blanket, but not sufi'icient to prevent the fibers of one unit from intermingling with those of another so that the fibers of the adjacent units of this insulating material practically intermingle and become a part of other adjacent insulating units.

Whereas in the devices of the prior art an effort has been made to arrange the insulation units of which the material is constructed in such manner as to overlap joints, that is not necessary with the materials of the present invention, in which the fibers are so loosely confined in separate units that they practically intermingle and form a fiat blanket of insulation having somewhat the form of a felt.

The present material may, however, be constructed of fibers which could not be so felted together or, if they were made into a felt according to the prior art, they would be so compact, dense, and tight that they would have only a fraction of the insulating value of the present materials.

The insulating fibers preferably employed in the present material consist of asbestos fibers known to the trade as Amosite. In this form of the material it is adapted to be used for temperatures up to 750 degrees F. Other fibers which may be similarly treated and used in this material are specially processed mineral wool fibers, such as rock wool in any of its conventional forms, and when the material is constructed with mineral wool it may be used for temperatures from 750 to 1,000 degrees F.

Sheets or blankets of insulating materials may be constructed according to the present method, including fibers of practically any kind, such as any of the known animal, vegetable, or mineral fibers, including fur, feathers, cotton, wool, linen,

etc., irrespective of the tensile strength of the fibers when assembled into an insulating unit, because the method of weaving contemplates the use of insulating units having practically no tensile'strength, and the threads employed are used primarily for interlacing and securing the fibers together, rather than to provide tensile strength during the weaving operation.

The material is best understood by considering also its mode of manufacture, which will be described briefiy. The fibers, such as Amosite asbestos fibers, are first carded, shortened, and fluffed out, or opened by a carding machine, whichmay be of conventional construction, except that the fibers in the fiufied or open condition are deposited upon a conveyor belt, disposed at the bottom of a trough, so that there is a constant stream of the carded and opened fibers coming from the discharge end of the machine. A plurality of cords, threads, or strands of suitable material are then fed from spools n the machine longitudinally into the stream of opened and carded Amosite fibers, these threads or strands comprising the cords 2G, 2!, 22 in Fig. l. The cords become immersed in the carded and opened fibers and emerge from the machine with it. At the point of discharge from the carding machine it is provided with a special arrangement which is adapted to wrap spirally about the loose Amosite fibers a plurality of insulating cords, such as the cords 23, 24 of Fig. 1, and

the cords embrace some of the loose Amosite fibers and bind them to the cords 222, but a large portion of the fibers, that is, most of the Arnosite fibers, still hang loosely together and project beyond the spiral cords 23, 24 in such manner that the insulating unit of Fig. l, which is indicated in its entirety by the numeral 25, is of irregular shape.

It is partially spirally shaped due to the tightening action of the cords 23, but it has practically no tensile strength for the purpose of weaving, and has only sufiicient tensile strength so that it may be coiled in a receptacle such as a cylindrical can, the can rotating as the insulating unit 25 emerges from the carding and wrapping machine, so that the unit is coiled therein.

Referring to Figs. '7 and 8, these are greatly enlarged disclosures of the cords used for weaving and wrapping the Amosite or other fibers, and these cords, arranged as indicated by the numeral 25, comprise a plurality of separate, twisted strands 2?, 28, 2d, which may be twisted in the same or opposite direction to their own twist, about one or more wires of steel, brass, or bronze 3t, 3!, which increase the tensile strength of the cord. The separate strands of the cords 2l-29 preferably are made of long asbestos fibers, capable of withstanding the high temperatures to which the sheet insulation or blanket are to be subjected.

Referring to Fig. l, the numeral 32 indicates the Amcsite fibers which are held by the cords 2 l- -2 3, but are permitted to project beyond those cords in such manner as to be capable of intermingling with any adjacent insulating units of the same character.

Referring to Fig. 3, this is a diagrammatic illustration of the interlacing arrangement of the three internal longitudinal cords and the two spirally wrapped cords. In some embodiments of the invention more or less of these cords may be used, and cords may also be spirally wrapped in opposite direction, if desired, but a minimum amount of such wrapping cords is preferably employed.

Referring to Fig. 2, it will be observed that the Amosite or other fibers 32 project beyond the spiral cords 23, 2s, and extend in random directions.

The methods and machines for making insulating materials according to the present invention form the subject of separate applications, Serial No. 195,117, filed March 10, 1938, and Serial No. 215,397 filed June 23, 1938, by me.

In brief, the machine for weaving the material of Fig. l differs radically from the prior weaving machines in that the insulating members 25 of Fig. l are not arranged on reels to be drawn from the reel into the weaving machine, but are conveyed from the coiled condition in cans by conveyor belts, which form a part of a carriage that is so arranged that it may actually carry and support the insulating unit or units 25 until these insulating units are laid upon a shelf forming a part of a comb of the Weaving machine so that the insulating unit or units 25 may be actually laid between the warp threads 33, 34 of the fabric of Figs. 4-6. I prefer to have conveyors of that weaving machine simultaneously convey a plurality of the insulating units 25 of Fig. 1 from the coiled condition, such as, for example, two or three of such units, preferably three, and they are carried over between the warp threads 33, 34 of the weaving machine, the Weaving machine being stopped while the insulating units 25 are put in place.

The insulating units 25 may be cut off at each side of the width of fabric, but I prefer to lay the insulating units from right to left, for example, as the carriage proceeds in between the warp threads 33, 34, and to catch and fold the insulating units 25 at the left side of the fabric, for example, forming a selvedge, and again relay three of the insulating units 25 from the left hand side of the fabric to the right hand side, as the carriage again emerges from between the warp threads 33, 34.

The operation of the carriage referred to and the loom are intermittent, the loom operating when the carriage does not operate, and the carriage operating when the loom does not operate. The carriage in one sense performs a similar function to a shuttle, except that it has a troughlike formation for carrying loose fibers into the space between the warp threads. At the right hand edge of the fabric, after the carriage emerges then the insulating members 25 are again caught and formed over to form a selvedge, when the carriage again goes into the machine between the warp threads 33, 34.

Referring to Fig. 6, it will thus be observed that there are six of the insulating units 25 between each fold of the warp threads 33, 34, but any other number of such insulating units may be used, and this is to be regarded as merely one example of the invention.

Referring to Figs. 4, 5, 6, it will also be observed that the weave of the fabric is of the simplest type, employing the insulating members 25 over assembly 36 and so on through the fabric.

Each assembly 35, 36 is preferably sprayed with a silicate solution at its edge 31, before the next assembly 38, for example, in Fig. 6, is woven into the fabric, this spray being applied in a sparing manner so as not to thoroughly wet the fibers,

but merely to cause the adjacent fibers of the units to adhere together.

The result of this process is a felted blanket which has better insulating characteristics than any of the insulating materials of the prior art.

The insulation may be constructed in any standard widths and thickness and, for example, one form of the insulation which is used for temperatures up to 750 degrees F. is constructed of Amosite fiber in rolls 50 feet long, sixty inches wide, and of standard thiclmess of one inch or threefourths of an inch, and greater thicknesses may be constructed by building up the felt in layers which are secured together by interlocking threads. Such insulation is light in weight, weighing about twelve pounds per cubic foot, and it is less than half as heavy as rigid asbestos of the prior art of the same insulating value.

Another form of the insulation which is made of specially processed mineral wool, such as rock wool, is manufactured in twenty-five foot rolls of forty inch width, one and one-half inches thick, weighing twenty-four pounds per cubic foot. Such materials may be applied directly to heated surfaces, and where especially high temperatures are present the fabric just referred to may be used to withstand temperatures from 750 to 1,000 degrees F.

Additional layers of the previously mentioned fabric made of Amosite fiber may be applied outside of the fabric just mentioned, to build up the insulation to the required thickness.

Referring to Fig. 9, these are curves showing the high insulating efficiency of Amosite fabric and mineral wool fabric constructed according to the present invention.

It will thus be observed that I have invented an improved insulation which is manufactured according to an improved method, and which has improved characteristics over the prior art.

The present insulation is lighter in weight and has a higher insulating value due to the fact that its fibers are kept in their most open and fluffy condition. The separate units of which the fabric is constructed, intermingle with each other and produce a continuous felt blanket which has no planes of separation or cracks, and the material has a substantially uniform insulating value over its entire area. It will withstand vibration and is permanently flexible and permanently efficient. It will not sag, and it may be removed and re-applied without deterioration. It has a high degree of flexibility, strength, and resiliency, so that it is not compacted by the application of severe abuse, such as, for example, foot traffic, which it withstands without injury. Its weight is approximately one-half of the weight of many of the block type materials of the prior art, and it may, therefore, be used in many applications where light wei ht is an important factor. It will withstand higher temperatures than the materials of the prior art when constructed with fibers of the preferred type described.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. An insulating blanket, comprising a plurality of warp threads spaced from each other, comprising asbestos fibers, and a plurality of closely adjacent and intermingling weft insulating members, said insulating members being arranged close to each other, and said warp threads being arranged alternately so that where one warp thread passes over a plurality of insulating weft members and under the next group of insulating weft members, the next adjacent warp threads pass under the first-mentioned insulating members and over the next mentioned group of insulating members, said insulating members comprising fluffed and open Amosite asbestos fibers having threads of asbestos intermingled therewith, at least one of said threads of each unit extending longitudinally of the insulating member and embedded therein, and another of said threads extending spirally of said insulating member for the purpose of holding said fibers together without confining the fibers or preventing the intermingling of adjacent insulating units.

2. An insulating blanket comprising a plurality of weft members and a plurality of transversely extending interwoven warp threads, said warp threads being spaced from each other, and said warp threads binding said weft" members together' to form a blanket, each of said weft-members comprising an assembly of flufied and open Amosite asbestos fibers having threads of asbestos intermingled therewith and extending longitudinally thereof, said latter threads of asbestos holding the flufi'e'd and open fibers in such manner that they extend at random directions and project laterally from the insulating member after the manner of a chenille member, and whereby the fibers of adjacent insulating units are adapted to intermingle with each other to form a substantially continuous insulating blanket.

3. An insulating blanket comprising a plurality of weft members and a plurality of transversely extending interwoven warp threads, said warp threads being spaced from each other, and said warp threads binding said weft members together to form a blanket, each of said weft members comprising an assembly of fiuffed and open Amosite asbestos fibers having threads of asbestos intermingled therewith and extending longitudinally thereof, said latter threads of asbestos holding the flufied and open fibers in such manner that they extend at random directions and project laterally from the insulating member after the manner of a chenille member, and whereby the fibers of adjacent insulating units are adapted to intermingle with each other to form a substantially continuous insulating blanket, and each of said weft members being adhesively joined at its abutting edges to adjacent Weft members with a limited amount of adhesive to prevent the formation of cracks between insulating weft members.

4. An insulating blanket comprising a plurality of warp threads spaced from each other and comprising non-combustible mineral fibers and a plurality of closely adjacent and intermingling weft insulating members, said insulating members being arranged close to each other, and said warp threads being arranged alternately so that a es-e11 where one warp thread passes over a plurality or insulating weft members and under the next group of weft insulating members, the next adjacent warp threads pass under the first-mentioned insulating members and over the next mentioned group of insulating members, said insulating members comprising fluffed and open non-combustible mineral fibers having threads of twisted mineral fibers intermingling therewith, at least one of the threads of each insulating member extending longitudinally of the insulating member and being embedded therein, and another of said threads extending spirally of said insulating member for the purpose of holding its fibers together without confining the fibers and preventing the intermingling of adjacent insulating units.

5. An insulating blanket comprising a plurality of warp threads spaced from each other and comprising non-combustible mineral fibers and a plurality of closely adjacent and intermingling weft insulating members, said insulating members being arranged close to each other, and said warp threads being arranged alternately so that where one warp thread passes over a plurality of insulating weft members and under the next group of Weft insulating members, the next adjacent warp threads pass under the first-mentioned insulating members and over the nextmentioned group of insulating members, said insulating members comprising fluiied and open rock wool fibers having threads of twisted mineral fibers intermingling therewith, at least one of the threads of each insulating member extending longitudinally of the insulating member and being embedded therein, and another of said threads extending spirally of said insulating member for the purpose of holding its fibers together without confining the fibers and preventing the intermingling of adjacent insulating units.

WILLIAM F. ASTLEY. 

